1. Field of the Invention
The present invention relates to a data receiving circuit that performs various signal processings on a reception signal received through a transmission line and to a method for receiving data.
2. Description of the Related Art
In recent years, there are increasing demands for high speed and high density data transmission, and a differential transmission system is proposed as a data transmission system that can meet such demands.
In the differential transmission system, information data is converted to a pair of differential signals having polarities different from each other, and the differential signals are transmitted over balanced transmission lines. As a data receiving circuit for receiving such differential signals, there is a proposed circuit that includes a differential input stage for inputting a pair of received differential signals and a level converting stage for converting the levels of the signals inputted to the differential input stage to a level that is usable by logical circuits, wherein the level obtained by the level converting stage is outputted as a data signal. See, for example, FIG. 1 of Japanese Patent Application Laid-Open Publication No. 2008-124697. In this data receiving circuit, a pair of received differential signals (IN1, IN2) are supplied to the gate terminals of transistors M81 and M82 respectively of the differential input stage (M80 to M84), and signals obtained by amplifying a difference value between these differential signals (IN1, IN2) are supplied to the level converting stage (M85 to M88) via lines 3 and 4.
Meanwhile, dispersions of the driving power and the parasitic capacitance of the transistors that are caused by their manufacturing process may result in rounding or delay of the signal waveform in the data receiving circuit described above. In particular, if the amplitudes of the signals in the data receiving circuit exceed the value expected at the time of designing the circuit, it becomes difficult to perform high speed processing, which may in turn lead to the generation of an erroneous data signal.